Computational study of dimethyl- and trimethyl-tin(IV) complexes of porphyrin derivatives

The molecular geometry, energetics and electronic charge distribution of diorgano- and triorgano-tin(IV) complexes of [protoporphyrin-IX] and [meso-tetra(4-carboxyphenyl)porphine] derivatives were determined at semi-empirical and ab initio levels. To study the molecular details of the complexes, simpler molecule models were calculated by the ab initio pseudo-potential method. The molecular properties of these complexes are essentially independent of the presence of the peripheral tin atoms. Agreement was always found among the results of the different computational approaches, as well as between the theoretical and the experimental findings on the molecular geometry of the hypothesized complexes. Interaction modes between water and the organo-tin systems considered were affected strongly by the presence of peripheral tin atoms. © 2001 John Wiley & Sons, Ltd.